Free developer tools
Format JSON, decode a JWT, test a regex, generate UUIDs and build meta tags in your browser. What you paste stays on your device, and there is no login.
Pasting an API response, a session token or a customer list into a random website is a risk most developers take without thinking. Every tool here does its work in your browser, so the JSON, JWT or password you paste is not sent to our server for processing. The pages are small, open without an account and work the same on a laptop or a phone.
There are 26 tools in five groups: data formats, tokens and encoding, SEO and links, design helpers, and validators for phone numbers, IBANs and Indian GSTIN, PAN and IFSC codes. Each one links to its siblings, so you can go from a JWT to its timestamps or from JSON to YAML in one click.
Format, convert and compare data
JSON, YAML, CSV, Excel and Markdown.
Tokens, IDs, encoding and security
Decode, encode, hash and generate.
SEO, links and the web
Meta tags, slugs, campaign links and browser details.
Design and content helpers
- CTA button generatorCopy-paste HTML button
- Colour palette generatorHex palettes, or colours from a photo
- Lorem ipsum generatorPlaceholder text, plain or HTML
- Colour contrast checkerWCAG AA and AAA, with passing fixes
- Gradient & shadow builderCSS gradients and box shadows
- SVG path editorEdit and simplify path data
Validate numbers and IDs
Format and checksum checks.
Guides
Step-by-step articles for these tools.
Frequently asked questions
Are these developer tools free?
Yes. There is no signup and no daily cap. Each tool is a single page that opens straight away.
Is my JSON, token or password uploaded?
No. These tools process what you paste on your device, in your browser. Each tool page explains its own processing details.
Does the JWT decoder verify my token?
Decoding only reads the header and payload. The JWT decoder can also check the signature with a key you paste; without that check, a decoded token proves nothing about who issued it.
Do they work on a phone?
Yes, in a modern mobile browser. Long JSON files and side-by-side diffs are easier to read on a laptop.